Money is the easiest to get in and out, and transactions are the most active. This is the main contract. From the data point of view, the contract with the largest turnover on that day is the main contract of that day.

The so-called main contract refers to the contract with the largest turnover. Because it is the most active contract in the market, basically all speculators are participating in this contract. It is also said that the main contract is the contract with the largest position, because generally speaking, the contract with the largest position is also the contract with the largest turnover.

The difference between futures and stocks is that the life cycle of futures contracts is limited and will not be delivered until after the last trading day of the contracts. The so-called main contract refers to the contract with the largest position. Under normal circumstances, the contract with the largest position has the largest turnover. Because it is the most active contract in the market and the easiest contract to clinch, speculators are basically participating in this contract.